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Variant insertion of the teres major muscle.

Iamsaard S, Thunyaharn N, Chaisiwamongkol K, Boonruangsri P, Uabundit N, Hipkaeo W - Anat Cell Biol (2012)

Bottom Line: The variation of TerMa insertion is very rare.In the shoulder and axillary regions of a 33-year-old Thai male cadaver, the variant insertion of the right TerMa was found.To explain an unusual movement of the arm, this rare variation of the TerMa insertion is necessary to be recognized.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. ; Integrative Complementary Alternative Medicine (ICAM) Research and Development Group, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.

ABSTRACT
The teres major (TerMa) muscle has a clinical significance for tendon transfer procedures in patients with massive rotator cuff tears. Individually, it originates from the dorsum of the inferior angle of scapula and inserts into the medial lip of bicepital groove of the humerus. Functionally, TerMa in cooperation with latissimus dorsi (LD) adducts arm, medially rotates arm, and assists in arm extension. The variation of TerMa insertion is very rare. In the shoulder and axillary regions of a 33-year-old Thai male cadaver, the variant insertion of the right TerMa was found. The muscle fibers of TerMa are directly attached at the supero-medial border of LD tendon. Notably, there was no terminal tendon of TerMa. To explain an unusual movement of the arm, this rare variation of the TerMa insertion is necessary to be recognized. This case report is very important for surgeons to preoperatively consider using the terminal tendon of TerMa for tendon transfer in treating patients with irreparable cuff tears.

No MeSH data available.


Related in: MedlinePlus

Photograph (A) and schematic drawing (B) (anterior axillary approach) showing the gross anatomy of the variant insertion of the teres major (A). Axil.a., axillary artery; BiB, biceps barchii; Br.Plex., brachial plexus; Cir.Sc.a., circumflex scapular artery; LD, latissimus dorsi; LDt, latissimus dorsi tendon; PecMa, pectoralis major; SS, subscapularis muscle; Sub.Sc.a., subscapular artery; TerMa, teres major; Tho.Do.a., thoracodorsal artery; Tho.Do.n., thoracodorsal nerve; black arrows, the connection area between TerMa muscle fibers and the LD tendon. Note: No terminal tendon of TerMa was observed.
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Figure 1: Photograph (A) and schematic drawing (B) (anterior axillary approach) showing the gross anatomy of the variant insertion of the teres major (A). Axil.a., axillary artery; BiB, biceps barchii; Br.Plex., brachial plexus; Cir.Sc.a., circumflex scapular artery; LD, latissimus dorsi; LDt, latissimus dorsi tendon; PecMa, pectoralis major; SS, subscapularis muscle; Sub.Sc.a., subscapular artery; TerMa, teres major; Tho.Do.a., thoracodorsal artery; Tho.Do.n., thoracodorsal nerve; black arrows, the connection area between TerMa muscle fibers and the LD tendon. Note: No terminal tendon of TerMa was observed.

Mentions: During routine dissection (at the Medical Gross Anatomy Laboratory in the Department of Anatomy, Faculty of Medicine, Khon Kaen University) of the embalmed cadavers for teaching medical and paramedical students, the shoulder and axillary regions were dissected and observed carefully to study the normal origins and insertions of the scapulohumeral muscles. We found an uncommon insertion of the right TerMa with typical origin in the embalmed cadaver of a 33-year-old Thai male (Fig. 1A). As an observation, TerMa muscle fibers inserted directly at the supero-medial border of the latissimus dorsi tendon (LDt) (Fig. 1A, B) and the medial lip of the bicipital groove, where this muscle usually attaches was empty. Compared to the normal TerMa's insertion, it was noted that the terminal tendon of TerMa was not observed. The width at the insertion border of TerMa muscle fibers to supero-medial border of LDt was approximately 7.2 cm (Fig. 1A, black arrows). This variant TerMa was innervated and supplied by lower subscapular nerve and circumflex scapular artery. In contrast, this variation of the left TerMa was not observed.


Variant insertion of the teres major muscle.

Iamsaard S, Thunyaharn N, Chaisiwamongkol K, Boonruangsri P, Uabundit N, Hipkaeo W - Anat Cell Biol (2012)

Photograph (A) and schematic drawing (B) (anterior axillary approach) showing the gross anatomy of the variant insertion of the teres major (A). Axil.a., axillary artery; BiB, biceps barchii; Br.Plex., brachial plexus; Cir.Sc.a., circumflex scapular artery; LD, latissimus dorsi; LDt, latissimus dorsi tendon; PecMa, pectoralis major; SS, subscapularis muscle; Sub.Sc.a., subscapular artery; TerMa, teres major; Tho.Do.a., thoracodorsal artery; Tho.Do.n., thoracodorsal nerve; black arrows, the connection area between TerMa muscle fibers and the LD tendon. Note: No terminal tendon of TerMa was observed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472149&req=5

Figure 1: Photograph (A) and schematic drawing (B) (anterior axillary approach) showing the gross anatomy of the variant insertion of the teres major (A). Axil.a., axillary artery; BiB, biceps barchii; Br.Plex., brachial plexus; Cir.Sc.a., circumflex scapular artery; LD, latissimus dorsi; LDt, latissimus dorsi tendon; PecMa, pectoralis major; SS, subscapularis muscle; Sub.Sc.a., subscapular artery; TerMa, teres major; Tho.Do.a., thoracodorsal artery; Tho.Do.n., thoracodorsal nerve; black arrows, the connection area between TerMa muscle fibers and the LD tendon. Note: No terminal tendon of TerMa was observed.
Mentions: During routine dissection (at the Medical Gross Anatomy Laboratory in the Department of Anatomy, Faculty of Medicine, Khon Kaen University) of the embalmed cadavers for teaching medical and paramedical students, the shoulder and axillary regions were dissected and observed carefully to study the normal origins and insertions of the scapulohumeral muscles. We found an uncommon insertion of the right TerMa with typical origin in the embalmed cadaver of a 33-year-old Thai male (Fig. 1A). As an observation, TerMa muscle fibers inserted directly at the supero-medial border of the latissimus dorsi tendon (LDt) (Fig. 1A, B) and the medial lip of the bicipital groove, where this muscle usually attaches was empty. Compared to the normal TerMa's insertion, it was noted that the terminal tendon of TerMa was not observed. The width at the insertion border of TerMa muscle fibers to supero-medial border of LDt was approximately 7.2 cm (Fig. 1A, black arrows). This variant TerMa was innervated and supplied by lower subscapular nerve and circumflex scapular artery. In contrast, this variation of the left TerMa was not observed.

Bottom Line: The variation of TerMa insertion is very rare.In the shoulder and axillary regions of a 33-year-old Thai male cadaver, the variant insertion of the right TerMa was found.To explain an unusual movement of the arm, this rare variation of the TerMa insertion is necessary to be recognized.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. ; Integrative Complementary Alternative Medicine (ICAM) Research and Development Group, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.

ABSTRACT
The teres major (TerMa) muscle has a clinical significance for tendon transfer procedures in patients with massive rotator cuff tears. Individually, it originates from the dorsum of the inferior angle of scapula and inserts into the medial lip of bicepital groove of the humerus. Functionally, TerMa in cooperation with latissimus dorsi (LD) adducts arm, medially rotates arm, and assists in arm extension. The variation of TerMa insertion is very rare. In the shoulder and axillary regions of a 33-year-old Thai male cadaver, the variant insertion of the right TerMa was found. The muscle fibers of TerMa are directly attached at the supero-medial border of LD tendon. Notably, there was no terminal tendon of TerMa. To explain an unusual movement of the arm, this rare variation of the TerMa insertion is necessary to be recognized. This case report is very important for surgeons to preoperatively consider using the terminal tendon of TerMa for tendon transfer in treating patients with irreparable cuff tears.

No MeSH data available.


Related in: MedlinePlus