The Shoulder Girdle. - Townsville Massage

The Shoulder Girdle.

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.

TrapeziusTrapezius.

The Trapezius Muscle has many functions:

  • Moving the shoulder blade in toward the spine.
  • Moving the shoulder blade up and down.
  • Bringing the head and neck in a backward direction.
  • To rotate and side bend the neck.
  • Assists in breathing.
  • Rotates the shoulder blade so that the upper-most part of the upper arm faces up.

The Effects on the Neck:

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 Trapezius Muscle is in four parts:

The upper fibres of the cervical vertebrae is the weakest part of the muscle and only provides minor elevation of the clavicle.

  • The area commonly known as’ Upper Traps’ is a strong elevator, rotator and retractor of the Scapula.
  • The mid-portion of the Trapzius is mainly responsible for scapula retraction.
  • The lower fibres of Trapezius assists in retraction and rotation.

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.

Action:

  • Laterally rotates, elevates and retracts Scapula. If Scapula is fixed, extends and laterally flexes neck.

Typical uses:

  • Shrugging shoulders.
  • Overhead movements.

Levator-ScapulaeLevator Scapulae.

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.

Action:

  • Elevates the scapula and gives lateral flexion of the cervical spine (each side independently)
  • Also responsible for the extension of the cervical spine (each side independently).

Typical use.

  • Shrugging shoulders.
  • Carrying a heavy shopping bag.

RhomboidsRhomboids.

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.

Action:

  • Retracts Scapula (bringing the shoulder blades together). Rotates Scapula downwards to rest position.

Typical use.

  • Pulling a draw open.

Pectoralis-MinorPectoralis Minor.

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.

Actions:

  • Elevates ribs if scapula fixed, protracts scapula (assists Serratus Anterior).
  • Rotation of the scapula downwards.

Typical use.

  • Pushing a door open.

Serratus-AnteriorSerratus Anterior.

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.

Actions:

  • Laterally rotates and protracts Scapula.

Typical use.

  • Reaching up to open a high window.

Sternocleidomastoid.

SCM

Sternocleidomastoid can clearly be seen when you turn your head to one side, on the opposite side of the neck.

Actions:

  • Flexes and laterally rotates cervical spine. Protracts head when acting together . Extends neck when neck already partially extended
  • Contraction on one side only: Laterally flexes (side bends) to the same side and rotates to the other.

Typical use:

  • Looking at the floor.
  • Looking over your shoulder.
  • Holding the phone between your ear and shoulder.
  • Generally being a sticky beak.