Lesson 10: Pectoralis Major, Latissimus Dorsi and Teres Major

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

Lesson 10: Pectoralis Major, Latissimus Dorsi and Teres Major

Study GuideQuick Reference - Pecs Lats and Teres Major

Note: If you intend to do the activities below do not open the "Study Guide" - all the answers are already filled in.  The study guide is just a quick reference tool, similar to flash cards - great for preparing for an exam.

Introduction:

In this lecture we will be discussing the Pectoralis Major, Latissimus Dorsi & Teres Major:

Etymology:

  • Pectoral (n.) early 15c., “ornament worn on the breast,” from Middle French pectoral and directly from Latin pectorale “breastplate,” noun use of neuter of adjective pectoralis (see pectoral (adj.)). – As a shortened form of pectoral muscle, attested from 1758. Slang shortening pec for this is first recorded 1966. Related: Pectorals; pecs. (Etymology Online)
  • Latissimus - From Latin lātissimus (“widest, broadest”), superlative of lātus (“wide, broad”) (Wiktionary)
  • Dorsidorsal (adj.) early 15c., from Old French dorsal (14c.) or directly from Medieval Latin dorsalis, corresponding to Latin dorsualis "of the back," from dorsum "back," of uncertain origin. (Etymology Online)
  • Teres - of latin origin referring to "round" or "cylindrical" (Wikipedia)
  • Majormajor (adj.) c.1300, from Latin maior (earlier *magjos), irregular comparative of magnus "large, great" (see magnate). (Etymology Online)

What joint do these muscles cross?

These muscles originate on the axial skeleton (except the Teres Major which originates on the lateral border of the scapula) and insert into the bicipital groove of the anterior humeral head.  These muscles cross the shoulder (glenohumeral joint) and assist in motion of the arm.  Although they may have an indirect role on scapular motion, in