Upper and Lower Limb Muscles

• The presentation covers the muscles of the upper and lower limbs.
• Dr. Ashraf Ramzy, Professor of Anatomy & Embryology, presents the material.

Muscles of the Upper Limb

Muscles of Pectoral Region

• The Pectoralis major has two heads of origin.
• The clavicular head originates from the medial ½ of the clavicle.
• The sternocostal head originates from the front of the sternum and the upper seven costal cartilages.
• The Pectoralis minor lies deep to the pectoralis major.
• Originates from the 3rd, 4th, and 5th ribs.
• The Serratus Anterior originates via eight fleshy slips from the top eight ribs.

Muscles of the Back

• There are five muscles that connect the upper limbs to the vertebral column.
• These muscles are arranged in two layers: superficial and deep.
• The superficial layer includes the Trapezius and Latissimus dorsi.
• The deep layer includes the Levator scapulae, Rhomboideus minor, and Rhomboideus major.
• The Trapezius originates from the skull, cervical and thoracic vertebrae.
• It inserts into the clavicle and scapula.
• The Latissimus Dorsi originates from the hip bone, thoracic vertebrae, and lower four ribs.
• It inserts into the humerus.
• Levator scapulae, Rhomboideus minor and Rhomboideus major originate from the cervical and thoracic vertebrae.
• They insert into the medial border of the scapula.

Muscles of the Shoulder

• There are six muscles that connect the scapula to the upper part of the humerus.
• They mostly originate from the scapula, and insert in the humerus.
• This includes:
• Supraspinatus.
• Infraspinatus.
• Teres minor.
• Teres major.
• Subscapularis.
• Deltoid.
• Supraspinatus is located in the supraspinous fossa, and the Infraspinatus resides in the infraspinous fossa.
• Subscapularis is located in the subscapular fossa.

Muscles of the Front of the Arm

• Contains 3 muscles
• This includes:
• Coracobrachialis, located in the upper half of the arm.
• Biceps brachii, which has two heads, a short and a long head.
• Action: Flexion of elbow and supination.
• Brachialis lies in the lower half of the arm.
• Action: Main flexor of the elbow.

Muscles of the Back of the Arm

• Contains one muscle, the Triceps brachii.
• Triceps brachii has three heads: long, medial, and lateral.
• The medial head lies deep to the other two heads.
• Action: Main extensor of the elbow.

Muscles of the Front of the Forearm

• There are eight being arranged in three layers: superficial, middle, and deep.
• Layer I, or superficial layer, consists of four muscles.
• Pronator teres.
• Flexor carpi radialis.
• Palmaris longus.
• Flexor carpi ulnaris.
• Action: All muscles involved in the flexion of wrist except pronator teres, which enable pronation of the forearm.
• Layer II is the middle layer contains one muscle.
• Flexor digitorum superficialis
• Action: Flexion of wrist and fingers.
• Layer III is the deep layer.
• Flexor pollicis longus
• Flexor digitorum profundus.
• Pronator quadratus.
• Action: All muscles enable flexion of the wrist and fingers save pronator quadratus, which enable pronation of the forearm.

Muscles of the Back of the Forearm

• Twelve muscles arranged in four groups.
• Group I: Three muscles acting on the thumb.
• Abductor pollicis longus.
• Extensor pollicis brevis.
• Extensor pollicis longus.
• Group II: Three RADIALIS muscles.
• Brachioradialis.
• Extensor carpi radialis longus.
• Extensor carpi radialis brevis.
• Group III: Three muscles acting on the medial 4 fingers.
• Extensor indicis.
• Extensor digitorum.
• Extensor digiti minimi.
• Group IV: Three miscellaneous muscles.
• Anconeus.
• Extensor carpi ulnaris.
• Supinator.

Muscles of the Lower Limb

Muscles of the Front of Thigh

• There are two main muscles in the front of the thigh: sartorius and quadriceps femoris.
• Both are supplied to the femoral nerve.
• Sartorius
• It is the longest muscle in the body.
• Action: Flexion, abduction, and lateral rotation of the hip, as well as flexion of the knee.
• Quadriceps Femoris has four heads: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.
• Nerve supply: Femoral nerve.
• Action: Extension of the knee.

Muscles of Medial Side of Thigh

• Includes 5 muscles
• Pectineus.
• Gracilis.
• Adductor longus.
• Adductor brevis.
• Adductor magnus: formed of 2 parts: pubic and ischial.
• Origin: From the hip bone.
• Insertion: In the femur, except for Gracilis, which is inserted in the Tibia.
• Nerve supply: Most muscles are supplied by the Obturator nerve.
• Action: adduction of the hip (thigh).

Muscles of Gluteal Region

• Contains two groups of muscles:
• Three Glutei Muscles:
• Gluteus maximus.
• Nerve Supply: Inferior gluteal nerve.
• Action: Main extensor of the hip.
• Gluteus medius.
• Gluteus minimus.
• Nerve Supply: Superior gluteal nerve.
• Action: Abduction of the hip.
• Six Short Lateral Rotators of the Hip:
• Piriformis.
• Obturator internus.
• Superior gemellus.
• Inferior gemellus.
• Quadratus femoris.
• Obturator externus.

Muscles of Back of Thigh

• Includes:
• Semitendinosus.
• Semimembranosus.
• Biceps femoris.
• Nerve supply: Sciatic nerve.
• Action:
• Extension of the hip.
• Flexion of the knee.

Muscles of Front of Leg

• Includes:
• Tibialis anterior.
• Extensor hallucis longus.
• Extensor digitorum longus.
• Peroneus Tertius.
• Nerve Supply: Anterior tibial nerve.
• Action:
• All muscles involved in extension (dorsiflexion) of ankle joint.
• Extensor hallucis longus enables extension of big toe.
• Extensor digitorum longus enable extension of lateral 4 toes.
• Tibialis anterior involved in inversion of foot.

Muscles of Lateral Side of Leg

• Includes:
• Peroneus longus.
• Peroneus brevis.
• Nerve supply: Superficial Peroneal nerve.
• Action: Eversion of the foot.

Muscles of Back of Leg

Superficial Group

• Gastrocnemius.
• Soleus.
• Plantaris.
• Popliteus.
• Nerve supply: Tibial nerve.
• Action: Plantar flexion of foot, with the exception of the popliteus, which aids in the rotation of the knee.

Deep Group

• Includes:
• Flexor hallucis longus.
• Flexor digitorum longus.
• Tibialis posterior.
• Nerve supply: Posterior Tibial nerve.
• Action: plantar flexion of foot and flexion of toes.