The upper limb is the region of the skeleton that is known for its mobility and dexterity. It is the area of the skeleton that is able to grasp, strike and conduct fine motor skills. It is supported and stabilized by various muscles attached to the ribs and vertebrae. The upper limb consists of four major parts:
- Shoulder
- Arm
- Forearm
- Hand
These areas can be sub-divided into various regions, which we will discuss later.
Shoulder
The shoulder is the proximal region of the the upper limb that attaches the trunk to the neck. It consists of 3 bones:
- Clavicle
- Scapula
- Humerus
The clavicle and the scapula form the pectoral (shoulder) girdle. The pectoral girdle is a bony ring that connects the upper limb to the axial skeleton.
Arm
The arm is the longest and first segment of the upper limb. It extends from the shoulder to the level of the elbow. It consists of the humerus and has a posterior and anterior compartment.
Forearm
The forearm is said to be the second longest segment of the upper limb. It extends from the elbow and the wrist. It is composed of an anterior and posterior compartment. It contains two bones:
- Ulna
- Radius
Hand
As we move distal from the forearm we have the hand. It is composed of the:
- Wrist
- Palm
- Dorsum of the hand
- digits
The hand is unique because it is important in order for us to grasp things and detect pain and temperature due the the rich supply of sensory nerve endings. The along contains of 27 bones in our bodies. In the next sections we will talk about the bones of the upper limb.