MBBS Anatomy โ Upper Limb (Detailed Notes &
Explanation)
1. Bones of Upper Limb
The upper limb skeleton provides structure and allows movement. Each bone has clinical
importance.
1Clavicle โ Acts as a strut between sternum and shoulder, commonly fractured.
2Scapula โ Flat bone forming shoulder blade; important for muscle attachment.
3Humerus โ Long bone of arm; surgical neck fractures can injure axillary nerve.
4Radius โ Lateral forearm bone; important for wrist movement.
5Ulna โ Medial forearm bone; forms elbow hinge joint.
2. Brachial Plexus
A network of nerves supplying the upper limb. It originates from spinal nerves C5โT1.
1Roots: C5โT1 spinal nerves.
2Trunks: Upper, Middle, Lower.
3Divisions: Each trunk divides into anterior and posterior.
4Cords: Lateral, Posterior, Medial.
Clinical: Erbโs palsy (C5โC6 injury) leads to 'waiter's tip' deformity. Klumpkeโs palsy (C8โT1)
causes claw hand.
3. Muscles of Arm
Muscles are divided into anterior (flexors) and posterior (extensors) compartments.
1Anterior: Biceps brachii (flexion), Brachialis (primary flexor), Coracobrachialis (adduction).
Innervated by musculocutaneous nerve.
2Posterior: Triceps brachii (extension). Innervated by radial nerve.
4. Important Nerves
Nerves control movement and sensation. Injury leads to characteristic deformities.
1Radial nerve โ Injury causes wrist drop.
2Median nerve โ Injury leads to ape thumb deformity.
3Ulnar nerve โ Injury results in claw hand.
