Transcript Document
Skeletal Muscles: Functional Groups 1. Prime movers • Provide the major force for producing a specific movement 2. Antagonists • Oppose or reverse a particular movement Copyright © 2010 Pearson Education, Inc. Skeletal Muscles: Functional Groups 3. Synergists • Add force to a movement • Reduce undesirable or unnecessary movement 4. Fixators • Synergists that immobilize a bone or muscle’s origin Copyright © 2010 Pearson Education, Inc. Naming Skeletal Muscles • Location—bone or body region associated with the muscle • Shape—e.g., deltoid muscle (deltoid = triangle) • Relative size—e.g., maximus (largest), minimus (smallest), longus (long) • Direction of fibers or fascicles—e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis) Copyright © 2010 Pearson Education, Inc. Naming Skeletal Muscles • Number of origins—e.g., biceps (2 origins) and triceps (3 origins) • Location of attachments—named according to point of origin or insertion • Action—e.g., flexor or extensor, muscles that flex or extend, respectively Copyright © 2010 Pearson Education, Inc. Muscle Mechanics: Arrangement of Fascicles • Circular • Fascicles arranged in concentric rings (e.g., orbicularis oris) • Convergent • Fascicles converge toward a single tendon insertion (e.g., pectoralis major) Copyright © 2010 Pearson Education, Inc. Muscle Mechanics: Arrangement of Fascicles • Parallel • Fascicles parallel to the long axis of a straplike muscle (e.g., sartorius) • Fusiform • Spindle-shaped muscles with parallel fibers (e.g., biceps brachii) Copyright © 2010 Pearson Education, Inc. Muscle Mechanics: Arrangement of Fascicles • Pennate • Short fascicles attach obliquely to a central tendon running the length of the muscle (e.g., rectus femoris) Copyright © 2010 Pearson Education, Inc. (a) (b) (g) (f) Circular (orbicularis oris) (c) (e) (c) Parallel (sartorius) (d) (e) Bipennate (rectus femoris) (f) Fusiform (biceps brachii) Copyright © 2010 Pearson Education, Inc. (b) Convergent (pectoralis major) (d) Unipennate (extensor digitorum longus) (g) Multipennate (deltoid) Figure 10.1 Major Skeletal Muscles of the Body • Grouped by function and location • Information for each muscle • Name and description—note information in the name • Origin and insertion—there is usually a joint between the origin and the insertion • Action—insertion moves toward origin; best learned by acting out muscle movement on one’s own body • Innervation—name of major nerve that supplies the muscle Copyright © 2010 Pearson Education, Inc. Head Temporalis Masseter Shoulder Trapezius Deltoid Arm Triceps brachii Biceps brachii Brachialis Forearm Pronator teres Brachioradialis Flexor carpi radialis Palmaris longus Pelvis/thigh Iliopsoas Pectineus Thigh Rectus femoris Vastus lateralis Vastus medialis Leg Fibularis longus Extensor digitorum longus Tibialis anterior Copyright © 2010 Pearson Education, Inc. Facial Epicranius, frontal belly Orbicularis oculi Zygomaticus Orbicularis oris Neck Sternohyoid Platysma Sternocleidomastoid Thorax Pectoralis minor Serratus anterior Pectoralis major Intercostals Abdomen Rectus abdominis Internal oblique Transversus abdominis External oblique Thigh Tensor fasciae latae Sartorius Adductor longus Gracilis Leg Gastrocnemius Soleus Figure 10.4 Arm Triceps brachii Brachialis Forearm Brachioradialis Extensor carpi radialis longus Flexor carpi ulnaris Extensor carpi ulnaris Extensor digitorum Iliotibial tract Leg Gastrocnemius Soleus Fibularis longus Calcaneal (Achilles) tendon Copyright © 2010 Pearson Education, Inc. Neck Epicranius, occipital belly Sternocleidomastoid Trapezius Shoulder Deltoid Infraspinatus Teres major Rhomboid major Latissimus dorsi Hip Gluteus medius Gluteus maximus Thigh Adductor magnus Hamstrings: Biceps femoris Semitendinosus Semimembranosus Figure 10.5 Muscles of the Head • Two groups 1. Muscles of facial expression 2. Muscles of mastication and tongue movement Copyright © 2010 Pearson Education, Inc. Muscles of Facial Expression • Insert into the skin • Important in nonverbal communication • All innervated by cranial nerve VII (facial nerve) Copyright © 2010 Pearson Education, Inc. Muscles of Facial Expression • Epicranius (occipitofrontalis) • Bipartite muscle consisting of the • Frontalis • Occipitalis • Galea aponeurotica—cranial aponeurosis connecting above muscles • The two muscles have alternate actions of pulling the scalp forward and backward Copyright © 2010 Pearson Education, Inc. Epicranius Corrugator supercilii Orbicularis oculi Levator labii superioris Zygomaticus minor and major Buccinator Risorius Orbicularis oris Mentalis Depressor labii inferioris Depressor anguli oris Platysma Copyright © 2010 Pearson Education, Inc. Galea aponeurotica Frontal belly Occipital belly Temporalis Masseter Sternocleidomastoid Trapezius Splenius capitis Figure 10.6 Muscles of Mastication and Tongue Movement • Four pairs involved in mastication • Prime movers of jaw closure • Temporalis and masseter • Grinding movements • Medial and lateral pterygoids Copyright © 2010 Pearson Education, Inc. Muscles of Mastication and Tongue Movement • All are innervated by cranial nerve V (trigeminal nerve) • Buccinator muscles (of facial expression group) also help by holding food between the teeth • Three muscles anchor and move the tongue • All are innervated by cranial nerve XII (hypoglossal nerve) Copyright © 2010 Pearson Education, Inc. Temporalis Orbicularis oris Buccinator Masseter (a) Copyright © 2010 Pearson Education, Inc. Figure 10.7a Lateral pterygoid Medial pterygoid (b) Copyright © 2010 Pearson Education, Inc. Masseter pulled away Figure 10.7b Tongue Styloid process Styloglossus Hyoglossus Stylohyoid Hyoid bone Genioglossus Mandibular symphysis Geniohyoid Thyroid cartilage Copyright © 2010 Pearson Education, Inc. Thyrohyoid (c) Figure 10.7c Muscles of the Anterior Neck and Throat • Most are involved in swallowing • Two groups 1. Suprahyoid 2. Infrahyoid Copyright © 2010 Pearson Education, Inc. Suprahyoid Muscles of the Anterior Neck and Throat • Four deep muscles are involved in swallowing (they move the hyoid bone and larynx) • Form the floor of the oral cavity • Anchor the tongue • Move the hyoid bone and the larynx Copyright © 2010 Pearson Education, Inc. Infrahyoid Muscles of the Anterior Neck and Throat • Straplike muscles that depress the hyoid and larynx as swallowing ends and during speaking Copyright © 2010 Pearson Education, Inc. Median raphe Anterior Digastric belly Posterior belly Stylohyoid (cut) Thyrohyoid Thyroid cartilage of the larynx Thyroid gland Sternothyroid Mylohyoid Stylohyoid Hyoid bone Omohyoid (superior belly) Sternohyoid Sternocleidomastoid Omohyoid (inferior belly) (a) Copyright © 2010 Pearson Education, Inc. Figure 10.8a Tensor veli palatini Levator veli palatini Styloid process Superior pharyngeal constrictor Middle pharyngeal constrictor Hyoid bone Thyrohyoid membrane Inferior pharyngeal constrictor (c) Esophagus Copyright © 2010 Pearson Education, Inc. Buccinator Mandible Mylohyoid (cut) Geniohyoid Hyoglossus Thyroid cartilage of larynx Trachea Figure 10.8c Muscles of the Neck and Vertebral Column • Two functional groups • Muscles that move the head • Muscles that extend the trunk and maintain posture Copyright © 2010 Pearson Education, Inc. Muscles of the Neck and Vertebral Column: Head Movement • Sternocleidomastoid—major head flexor • Suprahyoid and infrahyoid—synergists to head flexion • Sternocleidomastoid and scalenes—lateral head movements • Semispinalis capitis—synergist with sternocleidomastoid • Splenius (capitis and cervicis portions): head extension, rotation, and lateral bending Copyright © 2010 Pearson Education, Inc. 1st cervical vertebra Sternocleidomastoid Base of occipital bone Mastoid process Middle scalene Anterior scalene Posterior scalene (a) Anterior Copyright © 2010 Pearson Education, Inc. Figure 10.9a Mastoid process Splenius capitis Spinous processes of the vertebrae Splenius cervicis (b) Posterior Copyright © 2010 Pearson Education, Inc. Figure 10.9b Muscles of the Neck and Vertebral Column: Trunk Extension • Deep (intrinsic) back muscles • Erector spinae (sacrospinalis) group—prime movers of back extension and lateral bending • Iliocostalis • Longissimus • Spinalis • Semispinalis and quadratus lumborum— synergists in extension and rotation Copyright © 2010 Pearson Education, Inc. Mastoid process of temporal bone Longissimus capitis Iliocostalis cervicis Longissimus cervicis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis Erector Longissimus spinae Spinalis Iliocostalis lumborum External oblique Ligamentum nuchae Semispinalis capitis Semispinalis cervicis Semispinalis thoracis Multifidus Quadratus lumborum (d) Copyright © 2010 Pearson Education, Inc. Figure 10.9d Muscles of the Thorax • Muscles of respiration • External intercostals—more superficial muscles that elevate ribs for inspiration • Internal intercostals—deeper muscles that aid forced expiration • Diaphragm • Partition between thoracic and abdominal cavities • Most important muscle in inspiration • Innervated by phrenic nerves Copyright © 2010 Pearson Education, Inc. External intercostal (a) Copyright © 2010 Pearson Education, Inc. Internal intercostal Figure 10.10a Xiphoid process of sternum Foramen for inferior vena cava Central tendon of diaphragm Foramen for aorta 12th rib (b) Copyright © 2010 Pearson Education, Inc. Foramen for esophagus Costal cartilage Diaphragm Lumbar vertebra Quadratus lumborum Psoas major Figure 10.10b Muscles of the Abdominal Wall • Four paired muscles; their fasciae and aponeuroses form the lateral and anterior abdominal wall • Internal obliques • External obliques • Transversus abdominis • Rectus abdominis Copyright © 2010 Pearson Education, Inc. Pectoralis major Serratus anterior Linea alba Transversus abdominis Internal oblique External oblique Aponeurosis of the external oblique (a) Copyright © 2010 Pearson Education, Inc. Tendinous intersection Rectus abdominis Inguinal ligament (formed by free inferior border of the external oblique aponeurosis) Figure 10.11a Muscles of the Abdominal Wall • Fascicles of these muscles run at angles to one another, providing added strength • All are innervated by intercostal nerves • Actions of these muscles • Lateral flexion and rotation of the trunk • Help promote urination, defecation, childbirth, vomiting, coughing, and screaming Copyright © 2010 Pearson Education, Inc. Rectus abdominis Internal oblique External oblique IIiac crest Pubic tubercle Transversus abdominis Inguinal ligament Lumbar fascia Lumbar fascia (b) Copyright © 2010 Pearson Education, Inc. Figure 10.11b Muscles of the Pelvic Floor • Pelvic floor (pelvic diaphragm) is composed of two paired muscles • Levator ani • Coccygeus • Both are innervated by sacral nerves Copyright © 2010 Pearson Education, Inc. Muscles of the Pelvic Floor • Functions of the pelvic diaphragm • Seals the inferior outlet of the pelvis • Supports pelvic organs • Lifts pelvic floor to help release feces • Resists increased intra-abdominal pressure Copyright © 2010 Pearson Education, Inc. Muscles of the Perineum • Urogenital diaphragm • Anterior half of perineum, inferior to pelvic floor • Deep transverse perineal muscle • External urethral sphincter (voluntary control of urination) Copyright © 2010 Pearson Education, Inc. Anterior Levator ani Symphysis pubis Urogenital diaphragm Urethra Vagina Anal canal Pubococcygeus IIiococcygeus Obturator internus Coccyx Levator ani Coccygeus Piriformis (a) Copyright © 2010 Pearson Education, Inc. Posterior Pelvic diaphragm Figure 10.12a Urethral opening External urethral sphincter Inferior pubic ramus Deep transverse perineal muscle Central tendon Vaginal opening Anus External anal sphincter (b) Male Copyright © 2010 Pearson Education, Inc. Female Figure 10.12b Muscles of the Perineum • Muscles of superficial perineal space • Ischiocavernosus • Bulbospongiosus • Superficial transverse perineal muscles • External anal sphincter (in posterior half of perineum) Copyright © 2010 Pearson Education, Inc. Urethral opening Vaginal opening Clitoris Anus Penis Midline raphe Ischiocavernosus Bulbospongiosus Superficial transverse perineal muscle Levator ani Gluteus maximus (c) Male Copyright © 2010 Pearson Education, Inc. Female Figure 10.12c Superficial Muscles of the Thorax • Most are extrinsic shoulder muscles • Act in combination to fix the shoulder girdle (mostly the scapula) and move it to increase range of arm movements • Actions include elevation, depression, rotation, lateral and medial movements, protraction, and retraction • Two groups of muscles: anterior and posterior Copyright © 2010 Pearson Education, Inc. Superficial Muscles of the Thorax • Anterior extrinsic shoulder muscles • Pectoralis minor • Serratus anterior • Subclavius • (Pectoralis major considered later with muscles that act on the humerus) Copyright © 2010 Pearson Education, Inc. Sternocleidomastoid Deltoid Pectoralis major Sternum Biceps brachii (a) Copyright © 2010 Pearson Education, Inc. Subclavius Clavicle Subscapularis Pectoralis minor Coracobrachialis Serratus anterior Humerus Superficial Muscles of the Posterior Thorax • Posterior extrinsic shoulder muscles • Trapezius • Levator scpulae • Rhomboids (major and minor) • (Latissimus dorsi considered later with muscles that act on the humerus) Copyright © 2010 Pearson Education, Inc. Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Rhomboid minor Rhomboid major Spine of scapula Infraspinatus Teres minor Teres major Humerus Latissimus dorsi (c) Copyright © 2010 Pearson Education, Inc. Figure 10.13c Muscles Crossing the Shoulder Joint • Nine muscles cross the shoulder joint to insert on and move the humerus Copyright © 2010 Pearson Education, Inc. Muscles Crossing the Shoulder Joint • Some originate off the scapula; others originate off the axial skeleton • Three are prime movers of the arm • Pectoralis major • Latissimus dorsi • Deltoid • Actions include flexion, extension, adduction, abduction, and rotation of humerus Copyright © 2010 Pearson Education, Inc. Muscles Crossing the Shoulder Joint • Four muscles are rotator cuff muscles • Supraspinatus • Infraspinatus • Teres minor • Subscapularis • Reinforce the capsule of the shoulder • Act as synergists and fixators • Two additional muscles are synergists: coracobrachialis and teres major Copyright © 2010 Pearson Education, Inc. Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Copyright © 2010 Pearson Education, Inc. Figure 10.14a Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view Copyright © 2010 Pearson Education, Inc. * Rotator cuff muscles Figure 10.14b Copyright © 2010 Pearson Education, Inc. Table 10.12 Part 1 Muscles Crossing the Elbow Joint • Anterior flexor muscles • Brachialis and biceps brachii—chief forearm flexors • Brachioradialis—synergist and stabilizer Copyright © 2010 Pearson Education, Inc. Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Copyright © 2010 Pearson Education, Inc. Figure 10.14a Muscles Crossing the Elbow Joint • Posterior extensor muscles • Triceps brachii—prime mover of forearm extension • Anconeus—weak synergist Copyright © 2010 Pearson Education, Inc. Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view Copyright © 2010 Pearson Education, Inc. * Rotator cuff muscles Figure 10.14b Copyright © 2010 Pearson Education, Inc. Table 10.12 Part 2 Muscles of the Forearm • Actions: movements of the wrist, hand, and fingers • Most anterior muscles are flexors and insert via the flexor retinaculum • Most posterior muscles are extensors and insert via the extensor retinaculum Copyright © 2010 Pearson Education, Inc. Muscles of the Forearm • Some forearm muscles act to produce pronation and supination of the forearm Copyright © 2010 Pearson Education, Inc. Muscles of the Forearm • Pronators: pronator teres and pronator quadratus • Supinator: a synergist with the biceps brachii Copyright © 2010 Pearson Education, Inc. Muscles of the Forearm: Anterior Compartment • Flexors • Flexor carpi radialis • Palmaris longus • Flexor carpi ulnaris • Flexor digitorum muscles (superficialis and profundus) • Flexor pollicis longus Copyright © 2010 Pearson Education, Inc. Superficial transverse ligament of palm Palmar aponeurosis Flexor retinaculum Flexor digitorum superficialis Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Copyright © 2010 Pearson Education, Inc. Flexor pollicis longus Extensor carpi radialis longus Brachioradialis Pronator teres Medial epicondyle of humerus Medial head of triceps brachii Pronator quadratus Tendon of biceps brachii (a) Biceps brachii Figure 10.15a Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis (cut) Lumbricals Tendon of flexor pollicis longus Thenar muscles of thumb Tendon of flexor carpi ulnaris (cut) Pronator quadratus Flexor pollicis longus Flexor digitorum profundus Supinator (c) Copyright © 2010 Pearson Education, Inc. Figure 10.15c Muscles of the Forearm: Posterior Compartment • Extensors • Extensor carpi radialis longus and brevis • Extensor digitorum • Extensor carpi ulnaris • Extensor pollicis brevis and longus • Extensor indicis • Abductor pollicis longus Copyright © 2010 Pearson Education, Inc. Extensor expansion Tendons of extensor digitorum Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus Extensor digitorum Extensor carpi radialis brevis Extensor carpi radialis longus Tendons of extensor carpi radialis brevis and longus Extensor indicis Extensor digiti minimi Extensor carpi ulnaris Flexor carpi ulnaris Anconeus Insertion of triceps brachii Brachioradialis (a) Copyright © 2010 Pearson Education, Inc. Figure 10.16a Interossei Extensor indicis Extensor pollicis brevis Extensor pollicis longus Abductor pollicis longus Supinator Anconeus Olecranon process of ulna (b) Copyright © 2010 Pearson Education, Inc. Figure 10.16b Copyright © 2010 Pearson Education, Inc. Figure 10.12 Part 3 Intrinsic Muscles of the Hand • Small weak muscles • Lie entirely within the palm of the hand • Control precise movements of metacarpals and fingers (e.g., threading a needle) • Abductors and adductors of the fingers • Produce opposition—move the thumb toward the little finger Copyright © 2010 Pearson Education, Inc. Finger and Thumb Movements • Flexion • Thumb—bends medially along the palm • Fingers—bend anteriorly • Extension • Thumb—points laterally • Fingers—move posteriorly Copyright © 2010 Pearson Education, Inc. Intrinsic Muscles of the Hand • Three groups • Thenar eminence (ball of the thumb) • Hypothenar eminence (ball of the little finger) • Each of the above groups has a flexor, an abductor, and an opponens muscle • Midpalmar muscles: lumbricals and palmar and dorsal interossei extend the fingers • Interossei muscles also abduct and adduct the fingers Copyright © 2010 Pearson Education, Inc. Tendons of: Flexor digitorum profundus Flexor digitorum superficialis Third lumbrical Fourth lumbrical Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi Pisiform bone Flexor carpi ulnaris tendon Flexor digitorum superficialis tendons (a) First superficial layer Copyright © 2010 Pearson Education, Inc. Fibrous sheath Second lumbrical Dorsal interossei First lumbrical Adductor pollicis Flexor pollicis brevis Abductor pollicis brevis Opponens pollicis Flexor retinaculum Abductor pollicis longus Tendons of: Palmaris longus Flexor carpi radialis Flexor pollicis longus Figure 10.18a Flexor digitorum profundus tendon Flexor digitorum superficialis tendon Dorsal interossei Palmar interossei Adductor pollicis Opponens digiti minimi Flexor pollicis brevis Flexor digiti minimi brevis (cut) Abductor digiti minimi (cut) (b) Second layer Copyright © 2010 Pearson Education, Inc. Abductor pollicis brevis Opponens pollicis Flexor pollicis longus tendon Figure 10.18b Palmar interossei (c) Palmar interossei (isolated) Copyright © 2010 Pearson Education, Inc. Figure 10.18c Dorsal interossei (d) Dorsal interossei (isolated) Copyright © 2010 Pearson Education, Inc. Figure 10.18d Muscles Crossing Hip and Knee Joints • Most anterior muscles flex the femur at the hip and extend the leg at the knee (foreswing of walking) • Most posterior muscles extend the thigh and flex the leg (backswing of walking) • Medial muscles all adduct the thigh • All three groups are enclosed by the fascia lata Copyright © 2010 Pearson Education, Inc. Movements of the Thigh • Include flexion, extension, abduction, adduction, circumduction, and rotation • Thigh flexors pass in front of the hip joint • Iliopsoas (iliacus and psoas major): prime mover of flexion • Tensor fasciae latae • Rectus femoris • Assisted by medial adductors and sartorius Copyright © 2010 Pearson Education, Inc. 12th rib Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 12th thoracic vertebra 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Quadriceps femoris • Rectus femoris • Vastus lateralis • Vastus medialis Adductor longus Gracilis Adductor magnus Tendon of quadriceps femoris Patella Patellar ligament (a) Copyright © 2010 Pearson Education, Inc. Figure 10.19a Movements of the Thigh • Thigh extensors • Hamstring muscles (prime movers of extension) • Biceps femoris • Semitendinosus • Semimembranosus • Gluteus maximus (prime mover during forceful extension) Copyright © 2010 Pearson Education, Inc. Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps Short head femoris Semitendinosus Semimembranosus Hamstrings (a) Copyright © 2010 Pearson Education, Inc. Figure 10.20a Movements of the Thigh • Adductors (also medially rotate thigh) • Adductor magnus • Adductor longus • Adductor brevis • Pectineus • Gracilis Copyright © 2010 Pearson Education, Inc. Pectineus (cut) Adductor brevis Adductor longus Adductor magnus Femur (b) Copyright © 2010 Pearson Education, Inc. O = origin I = insertion Figure 10.19b Movements of the Thigh • Abductors • Gluteus maximus (also laterally rotates thigh) • Gluteus medius (also medially rotates thigh) • Gluteus minimus (also medially rotates thigh) • Piriformis (also laterally rotates thigh) • Obturator externus (also laterally rotates thigh) • Obturator internus (also laterally rotates thigh) • Gemellus (also laterally rotates thigh) Copyright © 2010 Pearson Education, Inc. Gluteus medius (cut) Gluteus minimus Superior gemellus Piriformis Obturator internus Obturator externus Quadratus femoris Inferior gemellus Gluteus maximus (cut) (c) Copyright © 2010 Pearson Education, Inc. Figure 10.20c Muscles of the Thigh that Move the Knee Joint • Quadriceps femoris—sole extensor of the knee • Hamstring muscles—flex the knee, and are antagonists to the quadriceps femoris Copyright © 2010 Pearson Education, Inc. 12th rib Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 12th thoracic vertebra 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Quadriceps femoris • Rectus femoris • Vastus lateralis • Vastus medialis Adductor longus Gracilis Adductor magnus Tendon of quadriceps femoris Patella Patellar ligament Copyright © 2010 Pearson Education, Inc. Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps Short head femoris Semitendinosus Semimembranosus Copyright © 2010 Pearson Education, Inc. Hamstrings Muscles of the Leg: Movements • Various leg muscles produce the following movements • Ankle—dorsiflexion and plantar flexion • Intertarsal joints—inversion and eversion of the foot • Toes—flexion and extension Copyright © 2010 Pearson Education, Inc. Muscles of the Anterior Compartment of the Leg • Primary toe extensors and ankle dorsiflexors • Tibialis anterior • Extensor digitorum longus • Extensor hallucis longus • Fibularis tertius (not always present) Copyright © 2010 Pearson Education, Inc. Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis (a) Copyright © 2010 Pearson Education, Inc. Figure 10.21a Muscles of the Lateral Compartment of the Leg • Plantar flexion and eversion of the foot • Fibularis longus • Fibularis brevis Copyright © 2010 Pearson Education, Inc. Patella Head of fibula Gastrocnemius Soleus Fibularis longus Extensor digitorum longus Fibularis brevis Flexor hallucis longus Fibular retinaculum Tibialis anterior Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis Lateral malleolus (a) Copyright © 2010 Pearson Education, Inc. 5th metatarsal Figure 10.22a Muscles of the Posterior Compartment of the Leg • Flexors of the foot and the toes • Gastrocnemius • Soleus • Plantaris • Popliteus • Tibialis posterior • Flexor digitorum longus • Flexor hallucis longus Copyright © 2010 Pearson Education, Inc. Plantaris Gastrocnemius Medial head Lateral head Tendon of gastrocnemius Calcaneal tendon Medial malleolus Lateral malleolus Calcaneus (a) Superficial view of the posterior leg. Copyright © 2010 Pearson Education, Inc. Figure 10.23a Gastrocnemius medial head (cut) Plantaris (cut) Gastrocnemius lateral head (cut) Popliteus Soleus (cut) Tibialis posterior Fibula Flexor digitorum longus Fibularis longus Tendon of tibialis posterior Fibularis brevis Flexor hallucis longus Medial malleolus Calcaneal tendon (cut) Calcaneus (c) The triceps surae has been removed to show the deep muscles of the posterior compartment. Copyright © 2010 Pearson Education, Inc. Figure 10.23c Copyright © 2010 Pearson Education, Inc. Table 10.17 Part 1 Copyright © 2010 Pearson Education, Inc. Table 10.17 Part 2 Intrinsic Muscles of the Foot • Help flex, extend, abduct, and adduct the toes • Support the arches of the foot along with some leg tendons • Extensor digitorum brevis—dorsal foot muscle that helps extend the toes Copyright © 2010 Pearson Education, Inc. Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis (a) Copyright © 2010 Pearson Education, Inc. Figure 10.21a Plantar Muscles • The plantar muscles occur in four layers 1. Superficial layer • Flexor digitorum brevis • Abductor hallucis • Abductor digiti minimi 2. Second layer • Flexor accessorius • Lumbricals Copyright © 2010 Pearson Education, Inc. Tendon of flexor hallucis longus Lumbricals Flexor hallucis brevis Flexor digiti minimi brevis Abductor hallucis Flexor digitorum brevis Flexor accessorius Abductor digiti minimi Calcaneal tuberosity (a) First layer (plantar aspect) Copyright © 2010 Pearson Education, Inc. Figure 10.24a Lumbricals Flexor hallucis brevis Flexor hallucis longus tendon Flexor digitorum longus (tendon) Flexor digiti minimi brevis Abductor digiti minimi Flexor accessorius Fibularis longus (tendon) Flexor digitorum longus (tendon) Flexor hallucis longus (tendon) (b) Second layer (plantar aspect) Copyright © 2010 Pearson Education, Inc. Figure 10.24b Plantar Muscles 3. Third layer • Flexor hallucis brevis • Adductor hallucis • Flexor digiti minimi brevis 4. Deepest layer • Plantar and dorsal interossei Copyright © 2010 Pearson Education, Inc. Adductor hallucis (transverse head) Adductor hallucis (oblique head) Interosseous muscles Flexor hallucis brevis Flexor digiti minimi brevis Fibularis longus (tendon) Flexor accessorius Flexor digitorum longus (tendon) Flexor hallucis longus (tendon) (c) Third layer (plantar aspect) Copyright © 2010 Pearson Education, Inc. Figure 10.24c Plantar interossei (d) Fourth layer (plantar aspect): plantar interossei Copyright © 2010 Pearson Education, Inc.