T1 Nerve Root (T1)

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Motor Innervation

T1 Nerve Root Skeletal Muscle Innervations
Muscle	Origin	Insertion	Innervation	Action
Pectoralis major	Clavicle (medial half)¹ Sternum¹ Costal cartilages 1-6¹ Rectus sheath (anterior layer)¹ [Clavicle (medial half)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Sternum](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Costal cartilages 1-6](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020] [Rectus sheath (anterior layer)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#origin) [@gilroyAtlasAnatomy2020]	Humerus (crest of greater tubercle)¹ [Humerus (crest of greater tubercle)](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#insertion) [@gilroyAtlasAnatomy2020]	Lateral pectoral n.¹ Medial pectoral n.¹ C5 - T1¹ [Lateral pectoral n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [Medial pectoral n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [C5](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) - [T1](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#nerve) [@gilroyAtlasAnatomy2020]	Clavicular & Sternocostal parts [Flexion](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] [Aids in respiration when shoulder is fixed](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] Entire muscle [Adduction](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020] [IR](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_major_muscle.html#action) [@gilroyAtlasAnatomy2020]
Pectoralis minor	3-5 ribs¹ [3-5 ribs](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#origin) [@gilroyAtlasAnatomy2020]	Coracoid process¹ [Coracoid process](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#insertion) [@gilroyAtlasAnatomy2020]	Medial pectoral n.¹ C8 - T1¹ [Medial pectoral n.](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#nerve) [@gilroyAtlasAnatomy2020] [C8](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#nerve) - [T1](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#nerve) [@gilroyAtlasAnatomy2020]	Respiration [Assists in respiration](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#action) [@gilroyAtlasAnatomy2020] Scapula [Depression](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#action) [@gilroyAtlasAnatomy2020] [Downward rotation](/The Archive/Anatomy/Skeletal Muscles/Upper Limb Muscles/Axioappendicular Anterior Muscles/pectoralis_minor_muscle.html#action) [@gilroyAtlasAnatomy2020]

Lesion

“Sensory disturbances occur on the medial arm. Paresis occurs variably in the following muscles: abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, all lumbricals and interossei, abductor digiti minimi, opponens digiti minimi, flexor digiti minimi, and adductor pollicis [16]. The finger flexor reflex (C8 T1) may be depressed. Sympathetic fibers destined for the superior cervical ganglia are interrupted, resulting in an ipsilateral Horner syndrome.”²

Examination

Muscle Strength

“Hand Intrinsics (T1) The patient is asked to squeeze the clinician’s fingers between their fingers while the clinician tries to pull their fingers away (Fig. 25-30). Based on the findings from the history, systems review, and key muscle testing, a sensory examination may be necessary (see Chapter 3).”³

References

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.

Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 8th ed. Wolters Kluwer Health; 2022.

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.

Citation

For attribution, please cite this work as:

Yomogida N, Kerstein C. T1 Nerve Root (T1). https://yomokerst.com/The Archive/Anatomy/Nerve Roots/t1_nerve_root.html