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Muscles of the Abdominal Wall

• Four paired muscles, their fasciae and aponeuroses form lateral and anterior abdominal wall– Rectus abdominis – External obliques– Internal obliques– Transversus abdominis

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Figure 10.12a Muscles of the abdominal wall.

Linea alba

Pectoralis major

Tendinous intersection

Rectus abdominis

Inguinal ligament(formed by free inferiorborder of the external oblique aponeurosis)

Aponeurosis of the external oblique

Transversus abdominis

Internal oblique

External oblique

Serratus anterior

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Muscles of the Abdominal Wall

• Fascicles run at angles to one another, provide added strength

• All innervated by intercostal nerves• Actions of these muscles

– Lateral flexion and rotation of trunk– Help promote urination, defecation, childbirth,

vomiting, coughing, and screaming

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PLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (b)

Figure 10.14a Superficial muscles of the thorax and shoulder acting on the scapula and arm.

Subclavius

Clavicle

Subscapularis

Pectoralis minor

Coracobrachialis

Serratus anterior

Humerus

Sternocleidomastoid

Deltoid

Pectoralis major

Sternum

Biceps brachii

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PLAY A&P Flix™: Movement of the pectoral girdle

PLAY A&P Flix™: Muscles of the pectoral girdle (c)

Superficial Muscles of the Posterior Thorax

• Posterior extrinsic shoulder muscles– Trapezius– Levator scapulae– Rhomboids (major and minor)

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Figure 10.14c Superficial muscles of the thorax and shoulder acting on the scapula and arm.

Levatorscapulae

Supraspinatus

Clavicle

Spine ofscapulaInfraspinatus

Teres minor

Teresmajor

Humerus

Trapezius

Deltoid

Rhomboidminor

Rhomboidmajor

Latissimusdorsi

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Muscles Crossing the Shoulder Joint

• Nine muscles cross shoulder joint; insert on and move humerus

• Some originate from scapula; others from axial skeleton

• Actions include flexion, extension, adduction

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Figure 10.15a Muscles crossing the shoulder and elbow joints, causing movements of the arm and forearm, respectively.

Clavicle

Deltoid

Sternum

Pectoralismajor

Coracobrachialis

Triceps brachii:Lateral headLong headMedial head

Bicepsbrachii

Brachialis

Brachio-radialis

Anterior view

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Figure 10.15b Muscles crossing the shoulder and elbow joints, causing movements of thearm and forearm, respectively.

Supraspinatus*

Spine of scapulaDeltoid (cut)

Greater tubercleof humerusInfraspinatus*

Teres minor*

Teres major

Triceps brachii: Lateral head Long head

Latissimus dorsi

Humerus

Olecranonof ulna

Anconeus

Posterior view

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Figure 10.16a Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers.

Superficialtransverseligament of palm

Palmaraponeurosis

Flexor digitorumsuperficialis

Flexor carpiulnarisPalmaris longusFlexor carpi radialis

Medial epicondyleof humerus

Medial head oftriceps brachii

Flexorretinaculum

Pronatorquadratus

Flexor pollicislongus

Extensor carpiradialis longus

Brachio-radialisPronatorteresTendon ofbiceps brachii

Biceps brachii

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Figure 10.16c Muscles of the anterior fascial compartment of the forearm acting on the right wrist and fingers.

Tendon of flexordigitorum superficialis(cut)

Lumbricals

Tendon of flexorpollicis longus

Thenar muscles of thumb

Pronator quadratus

Flexor pollicis longus

Flexor digitorumprofundus

Tendon offlexor digitorumprofundus

Tendon of flexor carpi ulnaris (cut)

Supinator

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Figure 10.17a Muscles of the posterior fascial compartment of the right forearm acting on the wrist and fingers.

Extensor expansion

Tendons of extensordigitorum

Extensor pollicislongusExtensor pollicisbrevisAbductorpollicis longus

Extensor digitorum

Extensor carpiradialis brevis

Extensor carpiradialis longus

Tendons of extensorcarpi radialis brevisand longus

Extensor indicis

Extensor digiti minimi

Extensor carpiulnaris

Flexor carpi ulnaris

Anconeus

Insertion oftriceps brachii

Brachioradialis

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A&P Flix™: Muscles that act on the hip joint and femur:An overview

PLAY

Muscles Crossing Hip and Knee Joints

• Most anterior muscles flex femur at hip, extend leg at knee (foreswing of walking)

• Most posterior muscles extend thigh, flex leg (backswing of walking)

• Medial muscles all adduct thigh• All three groups enclosed by fascia lata

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PLAY A&P Flix™: Anterior muscles that cross the hip joint

Movements of the Thigh

• Include flexion, extension, abduction, adduction, circumduction, and rotation

• Thigh flexors pass in front of hip joint– Iliopsoas (iliacus and psoas major) - prime

mover of flexion– Tensor fasciae latae– Rectus femoris– Assisted by medial adductors and sartorius

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12th ribQuadratus lumborumPsoas minorIliac crestIliopsoas Psoas major

Iliacus

12th thoracicvertebra

5th lumbarvertebraAnterior superior

iliac spineTensor fasciae lataePectineus

Sartorius Adductor longus

Quadriceps femoris • Rectus femoris

GracilisAdductor magnus

• Vastus lateralis

• Vastus medialis Tendon of quadriceps femoris

Patella

Patellarligament

Figure 10.20a Anterior and medial muscles promoting movements of the thigh and leg.

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Figure 10.21a Posterior muscles of the right hip and thigh.

Gluteus medius

Gluteusmaximus

Adductor magnus

GracilisIliotibial tract

Long headShort head

Bicepsfemoris

HamstringsSemitendinosusSemimembranosus

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Figure 10.22a Muscles of the anterior compartment of the right leg.

Fibularis longus

Gastrocnemius

Tibia

Tibialis anterior

Extensor digitorum longusSoleusExtensor hallucis longus

Fibularis tertius

Superior and inferiorextensor retinaculaExtensor hallucis brevis

Extensor digitorumbrevis

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Figure 10.23a Muscles of the lateral compartment of the right leg.

Fibular retinaculum

Fibularis brevis

Flexor hallucislongus

Lateral malleolus

Patella

Head of fibula

GastrocnemiusSoleusFibularis longusExtensor digitorum longus

Tibialis anterior

Extensor hallucis longusFibularis tertius

Superior and inferiorextensor retinacula

Extensor hallucisbrevisExtensor digitorumbrevis

Metatarsal V

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Muscles of the Posterior Compartment of the Leg

• Plantar flex ankle– Gastrocnemius– Soleus– Plantaris– Popliteus– Flexor digitorum longus– Flexor hallucis longus– Tibialis posterior

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Figure 10.24a Muscles of the posterior compartment of the right leg.

Plantaris

Gastrocnemius Medial headLateral head

Tendon ofgastrocnemius

Calcanealtendon Medialmalleolus

Superficial view of the posterior leg.

Lateral malleolus

Calcaneus

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Figure 10.24c Muscles of the posterior compartment of the right leg.

Gastrocnemiusmedial head(cut)

Flexor digitorumlongus

Tendon oftibialis posterior

MedialmalleolusCalcanealtendon (cut) Calcaneus

The triceps surae has been removed to show thedeep muscles of the posterior compartment.

Fibularis brevis

Flexor hallucislongus

Fibularislongus

FibulaTibialis posteriorSoleus (cut)Popliteus

Gastrocnemiuslateral head (cut)

Plantaris (cut)

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Figure 10.22a Muscles of the anterior compartment of the right leg.

Fibularis longus

Gastrocnemius

Tibia

Tibialis anterior

Extensor digitorum longusSoleusExtensor hallucis longus

Fibularis tertius

Superior and inferiorextensor retinaculaExtensor hallucis brevis

Extensor digitorumbrevis