Lesson 6: Joints of the Shoulder Girdle and Scapular Joint Actions

by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

Joints of the Shoulder Girdle:

  • The sternoclavicular joint - where the sternum meets the proximal end of the clavicle.

    • Etymology:

      • Sternum -  "breastbone," 1660s, from Greek sternon "chest, breast, breastbone" (in Homer, only of males), also "the breast as the seat of affections," related to stornynai "to spread out," from PIE *ster-no- "to stretch, extend," from root *stere-, *ster- "to spread," related to stornynai "to spread out" (see structure (n.)), on the notion of the chest as broad and flat, as opposed to the neck. Related: Sternal. (Etymology Dictionary)
      • Clavicle - Etymology: L, clavicula, little key (Medical Dictionary)

Sternoclavicular Joint Sternoclavicular Joint - By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below)Bartleby.com: Gray's Anatomy, Plate 325, Public Domain, https://commons.wikimedia.org/w/index.php?curid=85419

  • The acromioclavicular joint - where the acromion of the scapula meets the distal end of the clavicle

    • Etymology:

Acromioclavicular (AC) Joint Acromioclavicular Joint (AC Joint) - By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below)Bartleby.com: Gray's Anatomy, Plate 326, Public Domain, https://commons.wikimedia.org/w/index.php?curid=85420

Joint Actions of the Shoulder Girdle:

As discussed in a previous lesson, Joint Actions describe motion occurring at joints.  Much like anatomical directions, these terms are specific language (jargon) used to communicate motion between professionals. Joint actions are specific to Planes of Motion and in most cases are labeled relative to the Anatomical Position.

Special Notes about Shoulder Girdle (Scapular) Motion:

  • Although it may be referred to as the "scapulothoracic joint," the scapula is not a true joint. There is no bony connection between the scapula and the thorax.  In fact, the only joint holding