The shoulder girdle consists of a whole bunch of bony joints and muscles that connect the upper limbs to the rest of the skeleton and provide an impressive range of movement.
The three bones which form the Shoulder Girdle are the Scapula, the Clavicle, and the Humerus, and the most important feature of the shoulder is the large range of movement that it allows, which is of prime importance to daily life.
The Trapezius Muscle has many functions:
Because the Trapezius Muscle works to move the neck in several directions, its degree of tightness or looseness affects neck flexibility.
For people who work at desks and computers, or who spend many hours driving, the Upper Trapezius is that muscle above your shoulder that becomes very sore and painful.
The upper fibres of the cervical vertebrae is the weakest part of the muscle and only provides minor elevation of the clavicle.
Working together they have the effect of simultaneously lifting and retracting the Scapulae. The Trapezius is used most commonly to fix the Scapula to allow the Deltoid to move the Humerus.
Shrugging the shoulders (scapula elevation) involves the use of Levator Scapulae and Trapezius.
Fixation of the scapula by other muscles, allows the Levator Scapulae muscles to work together to aid cervical extension, or independently to laterally flex (side bend) the neck towards the side of the working muscle.
There are two rhomboid muscles – Rhomboid Major and Rhomboid Minor.
Rhomboid Major is larger and positioned below Rhomboid Minor. Chins and dips are excellent activities for developing these muscles.
The Pectoralis Minor muscle is the smallest of the two pectoral (chest) muscles.
It works together with the Serratus Anterior which protracts and rotates the Scapulae upwards.
When the two work together, pure protraction (without rotation) is produced.
The Serratus Anterior muscle is used in activities which draw the scapula forwards.
It is used strongly in push-ups and bench presses. Winged Scapulae are an indication of a weak Serratus Anterior.
Sternocleidomastoid can clearly be seen when you turn your head to one side, on the opposite side of the neck.