Figure 10.1 Patterns of fascicle arrangement in muscles. (b) (f) Circular (orbicularis oris) (b) Convergent (pectoralis major) (c) (e) (c) Parallel (sartorius) (d) Unipennate (extensor digitorum longus) (d) (e) Bipennate (rectus femoris) (f) Fusiform (biceps brachii) (g) Multipennate (deltoid)

(a) Mechanical advantage with a power lever Figure 10.2a Lever systems operating at a mechanical advantage and a mechanical disadvantage. Effort x length of effort arm = load x length of load arm (force x distance) = (resistance x distance) Effort 10 kg 0.25 cm Effort 25 cm Fulcrum Load 10 x 25 = 1000 x 0.25 250 = 250 1000 kg Load Fulcrum (a) Mechanical advantage with a power lever

(b) Mechanical disadvantage with a speed lever Figure 10.2b Lever systems operating at a mechanical advantage and a mechanical disadvantage. Effort 100 kg Effort Load 25 cm 50 cm Fulcrum Fulcrum 50 kg 100 x 25 = 50 x 50 2500 = 2500 Load (b) Mechanical disadvantage with a speed lever

Figure 10.3a Lever systems (1 of 2). (a) First-class lever Arrangement of the elements is load-fulcrum-effort Load Effort Fulcrum Load Effort Fulcrum Example: scissors

Figure 10.3a Lever systems (2 of 2). (a) First-class lever Arrangement of the elements is load-fulcrum-effort Fulcrum Load Effort In the body: A first-class lever system raises your head off your chest. The posterior neck muscles provide the effort, the atlanto-occipital joint is the fulcrum, and the weight to be lifted is the facial skeleton.

Figure 10.3b Lever systems (1 of 2). (b) Second-class lever Arrangement of the elements is fulcrum-load-effort Load Fulcrum Effort Load Effort Example: wheelbarrow Fulcrum

Figure 10.3b Lever systems (2 of 2). (b) Second-class lever Arrangement of the elements is fulcrum-load-effort Effort Load Fulcrum In the body: Second-class leverage is exerted when you stand on tip-toe. The effort is exerted by the calf muscles pulling upward on the heel; the joints of the ball of the foot are the fulcrum; and the weight of the body is the load.

Figure 10.3c Lever systems (1 of 2). (c) Third-class lever Arrangement of the elements is load-effort-fulcrum Load Effort Fulcrum Load Fulcrum Effort Example: tweezers or forceps

Figure 10.3c Lever systems (2 of 2). (c) Third-class lever Arrangement of the elements is load-effort-fulcrum Effort Load Fulcrum In the body: Flexing the forearm by the biceps brachii muscle exemplifies third-class leverage. The effort is exerted on the proximal radius of the forearm, the fulcrum is the elbow joint, and the load is the hand and distal end of the forearm.

Figure 10.4 Anterior view of superficial muscles of the body. Head Facial Temporalis Epicranius, frontal belly Orbicularis oculi Masseter Zygomaticus Shoulder Orbicularis oris Trapezius Neck Deltoid Sternohyoid Arm Platysma Triceps brachii Sternocleidomastoid Biceps brachii Thorax Brachialis Forearm Pectoralis minor Serratus anterior Pronator teres Pectoralis major Brachioradialis Intercostals Flexor carpi radialis Palmaris longus Abdomen Pelvis/thigh Rectus abdominis Iliopsoas Internal oblique Pectineus Transversus abdominis Thigh External oblique Rectus femoris Thigh Vastus lateralis Tensor fasciae latae Vastus medialis Sartorius Adductor longus Leg Gracilis Fibularis longus Leg Extensor digitorum longus Gastrocnemius Tibialis anterior Soleus

Figure 10.5 Posterior view of superficial muscles of the body. Neck Epicranius, occipital belly Sternocleidomastoid Arm Trapezius Triceps brachii Shoulder Brachialis Deltoid Forearm Infraspinatus Brachioradialis Teres major Extensor carpi radialis longus Rhomboid major Latissimus dorsi Flexor carpi ulnaris Hip Extensor carpi ulnaris Gluteus medius Gluteus maximus Extensor digitorum Iliotibial tract Thigh Adductor magnus Hamstrings: Leg Biceps femoris Gastrocnemius Semitendinosus Soleus Semimembranosus Fibularis longus Calcaneal (Achilles) tendon

Figure 10.6 Lateral view of muscles of the scalp, face, and neck. Epicranius Galea aponeurotica Corrugator supercilii Frontal belly Orbicularis oculi Occipital belly Levator labii superioris Zygomaticus minor and major Temporalis Buccinator Masseter Risorius Sternocleidomastoid Orbicularis oris Trapezius Mentalis Splenius capitis Depressor labii inferioris Depressor anguli oris Platysma

Figure 10.7a Muscles promoting mastication and tongue movements. Temporalis Orbicularis oris Masseter Buccinator (a)

Figure 10.7c Muscles promoting mastication and tongue movements. Styloid process Styloglossus Genioglossus Hyoglossus Mandibular symphysis Stylohyoid Hyoid bone Geniohyoid Thyrohyoid Thyroid cartilage (c)

Median raphe Anterior Mylohyoid belly Digastric Stylohyoid Posterior Figure 10.8a Muscles of the anterior neck and throat that promote swallowing. Median raphe Anterior belly Mylohyoid Digastric Stylohyoid Posterior belly Hyoid bone Omohyoid (superior belly) Stylohyoid (cut) Thyrohyoid Sternohyoid Thyroid cartilage of the larynx Sternocleido- mastoid Thyroid gland Omohyoid (inferior belly) Sternothyroid (a)

Base of occipital bone 1st cervical vertebra Mastoid process Middle Figure 10.9a Muscles of the neck and vertebral column causing movements of the head and trunk. Base of occipital bone 1st cervical vertebra Mastoid process Middle scalene Sternocleido- mastoid Anterior scalene Posterior scalene (a) Anterior

Mastoid process Splenius capitis Spinous processes of the vertebrae Figure 10.9b Muscles of the neck and vertebral column causing movements of the head and trunk. Mastoid process Splenius capitis Spinous processes of the vertebrae Splenius cervicis (b) Posterior

Sternocleidomastoid (cut) Platysma (cut) Internal jugular vein Figure 10.9c Muscles of the neck and vertebral column causing movements of the head and trunk. Sternocleidomastoid (cut) Platysma (cut) Internal jugular vein Omohyoid Sternohyoid Sternothyroid Sternocleidomastoid Pectoralis major (c)

Iliocostalis cervicis Semispinalis cervicis Longissimus cervicis Figure 10.9d Muscles of the neck and vertebral column causing movements of the head and trunk. Ligamentum nuchae Mastoid process of temporal bone Semispinalis capitis Longissimus capitis Iliocostalis cervicis Semispinalis cervicis Longissimus cervicis Semispinalis thoracis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis Erector spinae Longissimus Spinalis Multifidus Iliocostalis lumborum Quadratus lumborum External oblique (d)

Figure 10.10a Muscles of respiration. External intercostal (a) Internal intercostal

Figure 10.11a Muscles of the abdominal wall. Pectoralis major Serratus anterior Linea alba Tendinous intersection Transversus abdominis Internal oblique Rectus abdominis External oblique Aponeurosis of the external oblique Inguinal ligament (formed by free inferior border of the external oblique aponeurosis) (a)

Figure 10.11b Muscles of the abdominal wall. Rectus abdominis External oblique Internal oblique Lumbar fascia IIiac crest Pubic tubercle Lumbar fascia Transversus abdominis Inguinal ligament (b)

Sternocleido- Subclavius mastoid Clavicle Subscapularis Deltoid Figure 10.13a Superficial muscles of the thorax and shoulder acting on the scapula and arm. Sternocleido- mastoid Subclavius Clavicle Subscapularis Deltoid Pectoralis minor Pectoralis major Coracobrachialis Sternum Serratus anterior Biceps brachii Humerus (a)

Internal intercostals (seen through external intercostal membranes) Figure 10.13b Superficial muscles of the thorax and shoulder acting on the scapula and arm. Subclavius Deltoid Pectoralis minor Cephalic vein Pectoralis major Internal intercostals (seen through external intercostal membranes) Serratus anterior External oblique Rectus abdominis (b)

Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Spine of Figure 10.13c Superficial muscles of the thorax and shoulder acting on the scapula and arm. Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Spine of scapula Rhomboid minor Infraspinatus Rhomboid major Teres minor Teres major Humerus Latissimus dorsi (c)

Trapezius Deltoid Teres major Triceps brachii Latissimus dorsi (d) Figure 10.13d Superficial muscles of the thorax and shoulder acting on the scapula and arm. Trapezius Deltoid Teres major Triceps brachii Latissimus dorsi (d)

Levator scapulae Rhomboid minor Deltoid Infraspinatus Teres minor Figure 10.13e Superficial muscles of the thorax and shoulder acting on the scapula and arm. Levator scapulae Rhomboid minor Deltoid Infraspinatus Teres minor Teres major Rhomboid major Latissimus dorsi (e)

Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Figure 10.14a Muscles crossing the shoulder and elbow joint, causing movements of the arm and forearm, respectively. Clavicle Deltoid Sternum Pectoralis major Coracobrachialis Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view

Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle Figure 10.14b Muscles crossing the shoulder and elbow joint, causing movements of the arm and forearm, respectively. 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 * Rotator cuff muscles

Long head Biceps brachii Short head O = origin I = insertion (c) Figure 10.14c Muscles crossing the shoulder and elbow joint, causing movements of the arm and forearm, respectively. Long head Biceps brachii Short head O = origin I = insertion (c)

Superficial transverse ligament of palm Figure 10.15a Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers. Superficial transverse ligament of palm Palmar aponeurosis Flexor retinaculum Pronator quadratus Flexor digitorum superficialis Flexor pollicis longus Flexor carpi ulnaris Palmaris longus Extensor carpi radialis longus Flexor carpi radialis Brachioradialis Medial epicondyle of humerus Pronator teres Tendon of biceps brachii Medial head of triceps brachii Biceps brachii (a)

digitorum superficialis Figure 10.15b Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers. Tendon of flexor digitorum superficialis Tendon of brachioradialis (cut) Tendon of flexor carpi ulnaris (cut) Pronator quadratus Tendon of flexor carpi radialis (cut) Flexor pollicis longus Flexor digitorum superficialis Extensor carpi radialis longus Supinator Tendon of biceps brachii (cut) (b)

Tendon of flexor digitorum superficialis (cut) Tendon of flexor Figure 10.15c Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers. Tendon of flexor digitorum superficialis (cut) Tendon of flexor digitorum profundus 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)

Tendons of extensor carpi radialis brevis and longus Extensor pollicis Figure 10.16a Muscles of the posterior fascial compartment of the right forearm acting on the wrist and fingers. Extensor expansion Tendons of extensor digitorum Tendons of extensor carpi radialis brevis and longus Extensor pollicis longus Extensor indicis Extensor pollicis brevis Extensor digiti minimi Abductor pollicis longus Extensor carpi ulnaris Extensor digitorum Flexor carpi ulnaris Extensor carpi radialis brevis Anconeus Extensor carpi radialis longus Insertion of triceps brachii Brachioradialis (a)

Extensor pollicis brevis Figure 10.16b Muscles of the posterior fascial compartment of the right forearm acting on the wrist and fingers. Interossei Extensor indicis Extensor pollicis brevis Extensor pollicis longus Abductor pollicis longus Supinator Anconeus Olecranon process of ulna (b)

Figure 10.18a Hand muscles, ventral views of right hand. Tendons of: Flexor digitorum profundus Fibrous sheath Flexor digitorum superficialis Second lumbrical Dorsal interossei Third lumbrical First lumbrical Fourth lumbrical Adductor pollicis Flexor pollicis brevis Opponens digiti minimi Abductor pollicis brevis Flexor digiti minimi brevis Opponens pollicis Abductor digiti minimi Flexor retinaculum Pisiform bone Abductor pollicis longus Flexor carpi ulnaris tendon Tendons of: Palmaris longus Flexor digitorum superficialis tendons Flexor carpi radialis Flexor pollicis longus (a) First superficial layer

Figure 10.18b Hand muscles, ventral views of right hand. 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 pollicis brevis Abductor digiti minimi (cut) Opponens pollicis Flexor pollicis longus tendon (b) Second layer

Figure 10.18c Hand muscles, ventral views of right hand. Palmar interossei (c) Palmar interossei (isolated)

Figure 10.18d Hand muscles, ventral views of right hand. Dorsal interossei (d) Dorsal interossei (isolated)

Anterior superior iliac spine Tensor fasciae latae Pectineus Figure 10.19a Anterior and medial muscles promoting movements of the thigh and leg. 12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Adductor longus Sartorius Gracilis Quadriceps femoris Adductor magnus • Rectus femoris • Vastus lateralis • Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament (a)

O = origin I = insertion Vastus lateralis Vastus intermedius Vastus Figure 10.19c Anterior and medial muscles promoting movements of the thigh and leg. O = origin I = insertion Vastus lateralis Vastus intermedius Vastus medialis Rectus femoris tendon (cut) Patella Patellar ligament (c)

Figure 10.20a Posterior muscles of the right hip and thigh. Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps femoris Short head Hamstrings Semitendinosus Semimembranosus (a)

Figure 10.20b Posterior muscles of the right hip and thigh. Latissimus dorsi Erector spinae Lumbar fascia Gluteus medius External oblique Median sacral crest (of sacrum) Iliac crest Gluteus maximus (b)

Figure 10.20c Posterior muscles of the right hip and thigh. Gluteus medius (cut) Gluteus minimus Superior gemellus Piriformis Obturator internus Obturator externus Inferior gemellus Quadratus femoris Gluteus maximus (cut) (c)

Figure 10.21a Muscles of the anterior compartment of the right leg. 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)

Figure 10.21d Muscles of the anterior compartment of the right leg. O = origin I = insertion Extensor digitorum longus (d)

Figure 10.22a Muscles of the lateral compartment of the right leg. Patella Head of fibula Gastrocnemius Soleus Fibularis longus Extensor digitorum longus Tibialis anterior Extensor hallucis longus Fibularis tertius Fibularis brevis Superior and inferior extensor retinacula Flexor hallucis longus Extensor hallucis brevis Fibular retinaculum Extensor digitorum brevis Lateral malleolus (a) 5th metatarsal

Figure 10.23a Muscles of the posterior compartment of the right leg. Plantaris Medial head Gastrocnemius Lateral head Tendon of gastrocnemius Calcaneal tendon Medial malleolus Lateral malleolus Calcaneus (a) Superficial view of the posterior leg.

Figure 10.23b Muscles of the posterior compartment of the right leg. Lateral head (cut) Plantaris Gastrocnemius Medial head (cut) Popliteus Head of fibula Soleus Tendon of plantaris Fibularis longus Fibularis brevis Tendon of tibialis posterior (b) The gastrocnemius has been removed to show the soleus immediately deep to it.

Figure 10.24c Muscles of the right foot, plantar aspect. 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)

Figure 10.24e Muscles of the right foot, plantar aspect. Dorsal interossei (e) Fourth layer (dorsal aspect): dorsal interossei